Glossary

Every Pyth term you will see across the docs, the code, and the rest of this guide. Skim it once. Come back when you forget what expo means.

Aggregate price: The single canonical price for a feed, produced by Pythnet from publisher submissions using a weighted median.
Benchmarks: Pyth's archive of past signed price updates, accessible via the Benchmarks endpoint. Used for retrospective settlement and audits. A feature of Pyth Core.
Conf (confidence interval): A one-sigma error bar shipped with every price. Real value lies within price ± conf with high probability.
Entropy: Pyth's verifiable randomness service. Commit-reveal scheme delivered via callback to consumer contracts.
EntropyCallback: The function your contract implements to receive a verified random number from Entropy.
Expo: Signed exponent on a price. Real value = price × 10^expo. Almost always negative for crypto.
Express Relay: Sealed-bid auction system that routes contested transactions (liquidations, fills) to give MEV back to the protocol.
Feed ID: A 32-byte hex identifier for a specific market. Same ID works on every chain Pyth supports.
Hermes: The public web service that serves the latest signed price updates over HTTP and WebSocket. Free to use.
HermesClient: The official TypeScript/JavaScript SDK for talking to Hermes.
IPyth: The Solidity interface every EVM Pyth contract implements. Defines updatePriceFeeds, getPriceNoOlderThan, getUpdateFee.
Lazer: The former name for Pyth Pro. If you see it in old docs, blog posts, or third-party tutorials, read it as Pyth Pro.
Marketplace: Pyth's newest product. A platform for third-party data providers to list and monetize proprietary datasets through the Pyth distribution layer.
OIS (Oracle Integrity Staking): PYTH staking program where holders delegate stake to publishers. Slashable for bad prices, earns a share of fees.
Permissionless: No application, signup, or approval required to read Pyth Core feeds. Anyone can integrate.
Pyth Core: The flagship product. Decentralized, permissionless, pull-based price feeds — 3,059+ markets, available on 100+ chains.
Pyth Pro: Subscription-based, low-latency feed. ~1ms updates over WebSocket. Formerly known as Lazer. For perps, HFT, options vaults.
PriceStruct: The four-field on-chain price struct: { int64 price, uint64 conf, int32 expo, uint publishTime }.
Publisher: An institution that signs and submits prices to the network. 138+ of them today.
Pull oracle: Oracle pattern where the consumer fetches a fresh update on demand rather than relying on a scheduled push.
Pull update: A signed price payload retrieved from Hermes and posted on-chain by the consumer transaction.
Push oracle: Older oracle pattern where a keeper posts updates on a schedule. Costs gas even when nobody needs the price.
Pythnet: A Solana-based appchain that runs Pyth's aggregation. Publishers submit here. Aggregates exit through Wormhole.
PYTH (token): Native governance and staking token of the network. Used for OIS and DAO voting.
Sponsored feed: A feed whose updates are pre-funded by the chain or by Pyth. Reading is cheap; no need to fetch from Hermes.
Staleness: How old a stored price is. The maxAge in getPriceNoOlderThan rejects prices older than this.
Update fee: The protocol fee for posting an update on-chain. Always query with getUpdateFee, never hardcode.
VAA (Verifiable Action Approval): The signed cross-chain message format used by Wormhole. Carries Pyth updates between Pythnet and consumer chains.
Wormhole: The cross-chain messaging layer Pyth uses to relay signed prices from Pythnet to other chains.
getPriceUnsafe: Returns the most recent stored price. Will return a stale value if no fresh update arrived. Reserve for views/diagnostics, never for settlement.
getPriceNoOlderThan: Returns the price only if its publishTime is within maxAge seconds. Use this for any business-critical read.
updatePriceFeeds: Posts a signed update on-chain. Pay the fee returned by getUpdateFee.
parsePriceFeedUpdates: Validates signed updates without persisting them. Useful when you want the price inside one transaction but do not want to update on-chain storage.

Glossary

Every Pyth term you will see across the docs, the code, and the rest of this guide. Skim it once. Come back when you forget what expo means.

Aggregate price

The single canonical price for a feed, produced by Pythnet from publisher submissions using a weighted median.

Benchmarks

Pyth's archive of past signed price updates, accessible via the Benchmarks endpoint. Used for retrospective settlement and audits. A feature of Pyth Core.

Conf (confidence interval)

A one-sigma error bar shipped with every price. Real value lies within price ± conf with high probability.

Entropy

Pyth's verifiable randomness service. Commit-reveal scheme delivered via callback to consumer contracts.

EntropyCallback

The function your contract implements to receive a verified random number from Entropy.

Expo

Signed exponent on a price. Real value = price × 10^expo. Almost always negative for crypto.

Express Relay

Sealed-bid auction system that routes contested transactions (liquidations, fills) to give MEV back to the protocol.

Feed ID

A 32-byte hex identifier for a specific market. Same ID works on every chain Pyth supports.

Hermes

The public web service that serves the latest signed price updates over HTTP and WebSocket. Free to use.

HermesClient

The official TypeScript/JavaScript SDK for talking to Hermes.

IPyth

The Solidity interface every EVM Pyth contract implements. Defines updatePriceFeeds, getPriceNoOlderThan, getUpdateFee.

Lazer

The former name for Pyth Pro. If you see it in old docs, blog posts, or third-party tutorials, read it as Pyth Pro.

Marketplace

Pyth's newest product. A platform for third-party data providers to list and monetize proprietary datasets through the Pyth distribution layer.

OIS (Oracle Integrity Staking)

PYTH staking program where holders delegate stake to publishers. Slashable for bad prices, earns a share of fees.

Permissionless

No application, signup, or approval required to read Pyth Core feeds. Anyone can integrate.

Pyth Core

The flagship product. Decentralized, permissionless, pull-based price feeds — 3,059+ markets, available on 100+ chains.

Pyth Pro

Subscription-based, low-latency feed. ~1ms updates over WebSocket. Formerly known as Lazer. For perps, HFT, options vaults.

PriceStruct

The four-field on-chain price struct: { int64 price, uint64 conf, int32 expo, uint publishTime }.

Publisher

An institution that signs and submits prices to the network. 138+ of them today.

Pull oracle

Oracle pattern where the consumer fetches a fresh update on demand rather than relying on a scheduled push.

Pull update

A signed price payload retrieved from Hermes and posted on-chain by the consumer transaction.

Push oracle

Older oracle pattern where a keeper posts updates on a schedule. Costs gas even when nobody needs the price.

Pythnet

A Solana-based appchain that runs Pyth's aggregation. Publishers submit here. Aggregates exit through Wormhole.

PYTH (token)

Native governance and staking token of the network. Used for OIS and DAO voting.

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